Air pressure system for the skeleton wheels of an off-set printing press



Jan. 17, 1956 L. J. GRASSI 2,730,950

AIR PRESSURE SYSTEM FOR THE SKELETON WHEELS OF AN OFF-SET PRINTING PRESS 2 Sheets-Sheet 1 Filed July 26; 1954 fi f assi WM v ATTORNEYS Jan. 17', 1956 L. J. GRASS] AIR PRESSURE SYSTEM FOR THE SKELETON WHEELS OF" AN OFF-SET PRINTING PRESS 2 Sheets-Sheet 2 Filed July 26, 1954 INVENTOR Ill lxlraas 2 K WI ATTORNEYS United States Patent AIR PRESSURE SYSTEM FOR THE SKELETON WHEELS OF AN OFF-SET PRINTING PRESS Leon J. Grassi, Bronx, N. Y.

Application July 26, 1954, Serial No. 445,772

8 Claims. (Cl. 101-420) This invention relates to printing devices, and more specifically the invention pertains to an improvement in oflf-set printing presses.

It may be said that from the time of the conception of the off-set printing press, each of these machines which were adapted for commercial usage had inadvertently built therein a basic defect which, until the development of the present invention, defied all attempts of elimination. The fault or defect to which reference has been made arises at the sheet transfer mechanism on the delivery side of the press.

Every person skilled in this art is aware of the tendency of the skeleton wheels of an off-set printing press to cause streaking or lining of the printed side of a sheet. This difficulty reflects on the pride and reputation of every master printer and frequently results in financial loss in addition thereto. It should be recognized that a customer, in placing an order with a printer, anticipates that the work turned out will be substantially perfect. This too is the aim of the professional printer. However, in the event streaks or lines are present in the printed work, a downward adjustment of the price quoted to the customer is necessitated if the imperfect work is accepted, or it becomes a total loss if it is rejected by the customer.

Thus, one of the primary objects of this invention is to provide a skeleton wheel for an off-set printing press with means for positively preventing the streaking or lining of an impressed sheet after the sheet has been taken from the impression cylinder.

Another object of this invention is to provide a skeleton wheel of the type referred to above with means for preventing the sheet delivered to the discharge grippers from contacting the skeleton wheels during the period the sheet follows the orbit of the wheels.

A further object of this invention is to provide a skeleton wheel assembly for off-set printing presses, the assembly being provided with means for supplying a continuous fluid flow to the peripheries thereof to maintain a clearance between the skeleton wheels and the impressed sheet as the sheet travels around the orbit of the wheels.

A still further object of this invention is to provide a skeleton wheel assembly of an off-set printing press with means for continuously supplying to the periphery thereof a source of air under pressure as the impressed sheet is taken by the discharge grippers from the impression cylinder grippers to trace, without engaging the periphery of the wheels as the sheet is moved to the discharge end of the press.

Other and further objects and advantages of this invention will become more obvious from a consideration of the following specification when read in the light of the annexed drawings, in which:

Figure l is a perspective view of an air supply assembly for a plurality of skeleton wheels for an off-set printing press constructed in accordance with this invention and wherein, for the sake of clarity, the body portions of the wheels have been omitted.

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Figure 2 is a partial side elevation of the system, partly in cross-section, taken on the horizontal plane of line 2-2 of Figure 1, and looking in the direction of the arrows.

Figure 3 is a top plan view of the partial assembly shown in Figure 2.

Figure 4 is a cross-sectional view, partly in elevation, of a skeleton wheel constructed according to this inven tion, the view being taken on the vertical plane of line 4-4 of Figure 3, and looking in the direction of the arrows.

Figure 5 is an enlarged detail cross-sectional view taken on the line 5-5 of Figure 1, and looking in the direction of the arrows.

Figure 6 is an enlarged detail partial cross-sectional view taken on the horizontal plane of line 6-6 of Figure 4.

Figure 7 is a basic schematic illustration showing the relative position of the skeleton wheel assembly with respect to the primary elements of a conventional off-set printing press.

Referring now more specifically to the drawings, reference numeral 10 designates, in general, a conventional olf-set printing press (see Figure 7), wherein reference numeral 11 designates the plate cylinder which engages a blanket cylinder 12 that is, in turn, slightly spaced from the impression cylinder 13. Suitable means (not shown) feed a continuous stream of paper sheets 14 between the blanket cylinder 12 and the impression cylinder 13 to receive the off-set impression. Gripper means (not shown) are positioned on the impression cylinder and retain the print sheet thereon until the sheet reaches the discharge side of the off-set press. At that time, a second set of grippers known as the discharge side grippers 15 engage the leading edge of the sheets 14 and carry the sheets 14 around the peripheries of the skeleton wheels 10. After the sheets 14 have traveled the orbit of the skeleton wheels 10, the grippers then convey the sheets to a discharge pile bed (not shown). This is the conventional operation of all olf-set printing presses and it is the engagement of the sheets 14 with the skeleton wheels 10 that effects the streaking or lining of the printed sheets. The elimination of such lining or streaking is the end sought to be attained by the present invention, and a successful solution to this problem is achieved through an improvement in the conventional skeleton wheel assembly.

The reference numeral 16 designates, in general, a skeleton wheel constructed in accordance with the teachings of this invention. As is seen in Figures 2 to 4, inclusive, the skeleton wheel 16 comprises; a substantially flat, arcuately shaped disc 17 having a peripheral groove 18 bounded at its opposite sides by the side walls 19 and 26. One of the ends of the disc 17 is provided with a groove 21 defined by the side walls 22, 23, the open end of the groove 21 being in communication with the peripheral groove 18. A notch or recess 23 extends inwardly from the side wall 22 adjacent the lower end thereof to serve a function to be described.

A length of pipe 24 is disposed within the peripheral groove 18 and has an extension 25 thereof positioned within the groove 21. The extension 25 is bent laterally to pass through the slot 23 (see Figures 2 and 3) and continues in a portion 26 which is disposed substantially parallel to the longitudinal axis of the skeleton wheel shaft 27 supported for rotation in the opposite sides (not shown) of the printing press 10. As is clearly seen in Figure 4, the portion 26 of the tube 24 is bent downwardly at 28 and is again bent in a direction prependicular to the longitudinal axis of the shaft 27 in order to form an end and is secured to the other side 31 which serves to define the arcuate configuration of the disc 17. In the present case, the securing means are illustrated as comprising a countersunk bolt 32. As is seen in the drawings, each of tubes 24 is provided with a plurality of circumferentially spaced perforations 33 which communicate with the interior of the tube 24. a

1 The skeleton wheel 16 is provided with a substantially centrally disposed U-shaped opening 34, the base 35 thereof being substantially semi-circular in order to receive the shaft'27 therein. Key means 36 serve to lock the Wheel 16 for rotation with the shaft 27. A conventional locking lug (not shown) extends across the plateaus 37, 38 and the recess 34, and has its bifurcated end engaging beneath the opposite end of the pin 39 which extends trans versely of the disc 17 and projects from opposite sides thereof. Each of the discs 17 is provided with a transversely extending opening 40 to serve a purpose to be explained.

Reference is now made specifically to Figure l of the drawings wherein the skeleton wheel air supply system assembly is illustrated. As illustrated therein, it is seen that the. open end 29 of the tube24 is connected to. the stem 41 of a T-connector and one of the arms 42 of the connector is connected to one end of a tubular conduit 43 which is passed through the opening 40 formed in the wheel 16. The other end of the tube 43 is connected to one arm 44. of a second T-connector having its stem 45 connected with the open end 29a of a second length of tubing 24A. The other arm 45 of the second T-connector is connected to one end of a second conduit 46 which projects through the opening 40 formed in a second skeleton wheel 16 (not shown). The other end of the conduit 46 connects with one of the arms 47 of a third T- connector, the latter having its stem 48 connected with the open end of the third tubular member 248, the other arm 49 of the third T -connector being connected to one end of a third tubular conduit 50 which extends through an opening 40 formed in the third of the skeleton wheels 16. A manually operated bleeder valve 51 is connected to the other end of the conduit 50.

Thus it is seen that as the shaft 27 is driven by the conventional driving means (not shown) the skeleton wheels 16 will also rotate and at the same time turn around the longitudinal axis of the shaft 27, the conduits 43, 46, 50,

the T-connectors associated therewith, and the bleeder valve 51.

A two-part air housing, denoted in general by the reference numeral 52, is mounted on one end of the shaft 27.

One of the parts, 53, comprises a substantially cylindrical member having a central bore 54 extending axially thereof to receive one end of the shaft 27 therethrough. One end of the part 53 is bored inwardly to provide an annular air chamber 55 defined by the inner and outer cylindrical walls 56, 57' and the rear walls 58 extending therebetween.

One end of an air inlet fitting 59 is threaded into an opening' 60 (see Figure 5) formed in the cylindrical wall 57 and communicates with the chamber 55. The other end of the fitting 59 is connected with a stationary source of air under pressure (not shown) through the conduit 61. An arm member 62 is integrally formed with the cylindrical wall 57 and extends radially therefrom. The arm member is provided with a bifurcated outer end 65 which receives one end of a bolt 66 having its other end threaded into the inner side of one of the press side frame members (not shown). Thus it is seen that the member 53 is held against rotation with the shaft 27.

The other part of the housing 52 comprises an elongated cylindircal member 67 having a pair of opposed open and closed ends. The closed end 68 is centrally apertured at 69 to receive the shaft 27 and the open end thereof is telcscoped over the end 57 adjacent the open end. of the member 53. As is seen in the drawings, the end 57 is reduced in outside diameter to substantially equal the inside diameter of the member 67.

The closed end 68 is transversely bored at 70 and communicates at its inner end with the chamber 55 while the other end thereof is threadedly connected with one end of a fitting 71. The other end of the fitting 71 is connected to one end of a conduit 72 having its other end connected to the other end 73 of the first of the above described T-connectors.

The closed end 68 is provided with a threaded passage 74 which extends perpendicular to the axis of the shaft 27 and receives a set screw 75 which engages within the conventional keyway 27' extending longitudinally of the shaft 27.

From the above it is readily ascertainable that while the part 53 is fixed against rotation with the shaft 27, the part 67 will rotate therewith and with the air assembly of the skeleton wheels 16.

In operation, air is supplied under pressure to the chamber 55 through the conduit 61. The air is discharged through the passage 70, conduit 72 and enters the first of the T-connectors to conduit 43, the second T-connector, conduit 46, the third T-connector, and conduit 50 to the bleeder valve 51. The tubular members 24, 24A, and 2413, having their respective end portions 29, 29a and 29b connected with the stems 41, 45 and 48 of the T-connectors are also supplied with air which is discharged through the outlet ports 33, 33a and 33b.

The air pressure is regulated at its source to provide a sufiicient force at the discharge ports 33, 33a and 33b whereby as the sheet 14 is engaged by the discharge side grippers 15, the air striking against the sheet 14 will hold the sheet in spaced relation relative to the skeleton wheels 16 as the sheet follows their respective orbits to the discharge pile.

The bleeder valve 51 is adjusted to maintain'a flow of air through the openings 33 of each skeleton wheel 16 at substantially equal pressure of between 10 and 25 pounds, depending on the weight of an individual sheet 14.

The shaft 27 is standard and is formed of steel machined to a very smooth finish. The two part housing 52 is formed of aluminum and the bore 54 is machined to a tolerance of +0.002 of an inch relative to the diameter of the shaft 27. The bore 69 is substantially equal to the diameter of the shaft 27. The inside diameter of the cylindrical wall 67 and the outer surface of the end wall 57' are also machine finished. The inside diameter of the Wall 67 is permitted a tolerance of +0.002 inch.

Having described and illustrated one embodiment of this invention in detail, it is to be understood that the same is otfered'by way of example, and that the invention is to be limited only by the scope of the following claims.

What is claimed is:

l. A' skeleton wheel for an off-set printing press comprising a substantially flat arcuately shaped dischavinga centrally positioned opening formed therein, said disc.having a peripheral groove formed therein communicating at one of its ends with a groove extending along one of the sides defining the arc, an elongated substantially hollow cylindrical tube disposed in said peripheral groove and having a portion thereof extending into said groove formed in said side, said portion of said tube having an end section projecting laterally with respect to a side of said disc and connected with a source of air under pressure, the other end of said tubular member being closed, means for securing said tubular member in said grooves, and a plurality of spaced air outlet ports extending transversely through the wall of that part of the tubular member disposed in said peripheral groove.

2. In combination with an off-set printing press of the type having a plate cylinder, a blanket cylinder, an impression cylinder, a shaft mounted parallel to and on the delivery side of said impression cylinder, a pluralityof spaced skeleton wheels mounted on said shaft and adapted to rotate therewith, each of said wheels comprising a sub,- stantially flat arcuately shaped disc having a centrally positioned shaft receiving opening formed therein, said disc having a peripheral groove formed therein having an end thereof communicating with one end of a groove formed in and extending along one of the sides of the disc which defines the are, an elongated substantially hollow tubular member having an open and a closed end disposed in said peripheral groove and having a portion thereof extending into said groove formed in said side, said portion of said tubular member disposed in said side groove having a laterally projecting section including said open end, said disc having a second opening extending transversely thereof adjacent the other side thereof defining said arc, a second elongated substantially hollow tubular member having opposed open and closed ends, said second tubular member extending through said second openings in said disc, means connecting said open end of each of said first tubular members with said second tubular member and means connecting said open end of said second tubular member with a source of air under pressure.

3. In combination with an off-set printing press of the type having a plate cylinder, a blanket cylinder, an impression cylinder, a shaft mounted parallel to and on the delivery side of said impression cylinder, a plurality of spaced skeleton wheels mounted on said shaft and adapted to rotate therewith, each of said wheels comprising a substantially flat arcuately shaped disc having a centrally positioned shaft receiving opening formed therein, said disc having a peripheral groove formed therein having an end thereof communicating with one end of a groove formed in and extending along one of the sides of the disc which define the arc, an elongated substantially hollow tubular member having an open and a closed end disposed in said peripheral groove and having a portion,

thereof extending into said groove formed in said side, said portion of said tubular member disposed in said side groove having a laterally projecting section including said open end, said disc having a second opening extending transversely thereof adjacent the other side thereof defining said arc, a second elongated substantially hollow tubular member having opposed open ends, said second tubular member extending through said second openings in said disc, means connecting said open end of each of said first tubular members with said second tubular member, means connecting one end of said second tubular member with a source of air under pressure, and valve control means connected with the other end of said second tubular member.

4. Apparatus for supplying a fluid to an element rotatably mounted on a shaft comprising an elongated hollow cylindrical member having opposed open and closed ends, a substantially hollow cylindrical wall disposed within said cylindrical member and having an end thereof secured to said closed end of said member, said member and wall having a coaxial relation to define an annular chamber therebetween, a substantially hollow cylindrical closure member for the open end of said hollow cylindrical member, said closure member having opposed open and closed ends with said open end telescopically mounted over the open end of said cylindrical member, said closure member being rotatable relative to said cylindrical member, said closure member having an off-center opening forming a fluid outlet port extending transversely of its said closed end and in registry with said chamber, said opening upon rotation of said closure member tracing the open end of said chamber, said cylindrical member having an opening extending transversely therethrough and communicating with said chamber to form a fluid inlet port, said closed ends of said closure member and said cylind1ical member having centrally formed openings therein, said centrally formed openings having a diameter substantially equal to the inner diameter of said cylindrical wall whereby said telescoped closure member and cylindrical member are adapted to be mounted on said shaft, means keying said closure member to said shaft for rotation therewith, fluid passage means connecting said outlet port with said element to be supplied, said means rotating with said element and said closure member, means retaining said cylindrical member against rotation, and means connecting said inlet port with a source of fluid under pressure.

5. Apparatus for supplying a fluid under pressure to a plurality of elements mounted on a shaft and rotatable therewith, said elements having at least one fluid discharge port therein, said apparatus comprising an elongated substantially hollow cylindrical member and a coaxially positioned inner cylindrical wall adapted for mounting on said shaft, a bridging wall connecting one end of said cylindrical wall with one end of said cylindricai member to define an annular chamber having opposed open and closed ends, said cylindrical wall having a fluid inlet port formed therein communicating with said chamber, means preventing said cylindrical memher and cylindrical wall from rotating, a cylindrical closure member for said cylindrical member and cylindrical wall, said closure member having opposed open and closed ends and being telescopically mounted on said open end of said cylindrical member, and extending thereacross, said closed end of said closure member having a central opening formed therein to slidably receive said shaft therethrough, means keying said closure member to said shaft, said closed end of said closure member having an off-center opening formed therein in registry with said chamber whereby rotation of said closure member relative to said cylindrical member causes said last named opening to trace the outer open end of said chamber to form an air outlet port, fluid passage means connecting said outlet port with said elements and said discharge ports of said elements.

6. l n combination with an ofif-set printing press of the type having a plate cylinder, a blanket cylinder, an impression cylinder, a shaft mounted parallel to and on the delivery side of said impression cylinder, a plurality of spaced skeleton wheels mounted on said shaft and adapted to rotate therewith, each of said wheels comprising a substantially flat arcuately shaped disc. having a centrally positioned opening to receive said shaft thereto, means securing said disc to said shaft for rotation therewith, said disc having a peripheral groove formed therein having an end thereof communicating with one end of a second groove extending along one of the sides of said disc which define the arc, an elongated substantially hollow tubular member having an open and a closed end disposed in said peripheral groove and having a portion thereof extending into said groove formed in said side, said portion of said tubular member having a laterally projecting section including said open end of said tubular member, means connecting each of said open ends of said tubular members to a common conduit, fluid pressure control means mounted on one end of said conduit, means mounted on said shaft for supplying a source of fluid under pressure to the other end of said conduit, said means comprising a pair of coaxially spaced inner and outer substantially hollow cylindrical members connected adjacent one of their respective adjacent ends by a bridging wall and defining a substantially hollow annular chamber therebetween, said cylindrical members being mounted on said shaft in coaxial relation with said shaft rotatable in the inner tubular member, means connected with said outer cylindrical member to prevent rotation thereof, a fluid inlet port extending through said outer cylindrical member and communicating with said chamber, means connecting said inlet port with a source of fluid under pressure, an elongated substantially hollow cylindrical closure cap having opposed open and closed ends, said open end of said cap being telescoped over the open ends of said cylindrical members with said closed end of the former extending across the open ends of the latter, said closed end of said cap having a fluid outlet opening extending transversely thereof and in registry with said chamber whereby rotation of said cap relative to said cylindrical members causes said fluid outlet to trace the open end of said chamber, means connecting the other end of said conduit with said fluid outlet, and means keying said closure means to said shaft for rotation therewith.

7. An article of manufacture comprising a first elongated'snbstantially hollow cylindrical member having opposed open and closed ends, an endless wall extending axially of said cylindrical member and having a pair of opposed open ends with one of said last named ends secured to said closed end of said cylindrical mem w, means on said cylindrical member for fixedly mounting said cylindrical member on a support, a second cylindrical member having opposed open and closed ends, said second cylindrical member having the open end thereof telescopically mounted on said open end of said first cylindrical member with said closed end of said second cylindrical member extending across said open end of said first cylindrical member, said second cyiindrical member being rotatable relative to said first cylin- '2' tending inwardly from one end thereof, said cylindrical member having a circular passageway extending coaxially thereof and concentrically with respect to said annular chamber, said cylinder wall having an opening extending therethrough and having the inner end thereof in open communication with said annular chamber, said opening comprising an air inlet port, an elongated arm having an end thereof fixedly secured to said cylindrical member adiacent the other end thereof, the other end of said arm terminating in a bifurcation, an elongated sul'istantialiy hollow cylindrical closure member for said open end of said cylindrical member, said closure member having a pair of opposed open and closed ends, said closed end having an opening extending transversely therethrc-ugh and in communication with the open end of said annular chamber, said closed end having a centrally positioned aperture extending transversely therethrough having a diameter substantially equal to the diameter of said passageway, and said open end of said hollow cylindrical member being telescoped within the open end of said closure member.

References Cited in the file of this patent UNITED STATES PATENTS 2,299,259 Sites Oct. 20, 1942 2,450,599 Kloda Oct. 5, 1948 FOREIGN PATENTS 451,313 Germany Oct. 25, 1927 

